1. Field of the Invention
The present invention relates to a zoom lens, a camera apparatus, and a portable information terminal device.
2. Description of the Related Art
Digital cameras are experiencing an increase in image quality, as well as greater miniaturization, an increasingly wide angle of photography, and a greater magnification of an image that is taken with such a device. A demand exists for a high performance, miniature, wide angle, large aperture digital camera that includes a zoom lens with a 6× or greater magnification as a photographic lens thereof, and that is capable of achieving a high image quality that supports a photosensitive element in excess of 10 megapixels.
Whereas Japanese Patent Application Publication No. 2004-271937 discloses a configuration of five lens groups, which are arranged negative focal length-positive focal length-negative focal length-positive focal length-positive focal length, in order from nearest to furthest from a photographic subject, and which closely approaches a 5× magnification, such as a zoom lens according to the present invention. Such a configuration is not capable, however, of fulfilling the extant demand for a magnification of 6× or greater.
In addition, a configuration is known that installs a reflective photosensitive element within the zoom lens, thereby refracting a light path therein, in order to respond to the increasing miniaturization of the digital camera. Japanese Patent Application Publication No. 2004-102219 and Japanese Patent Application Publication No. 2005-338143 disclose an invention thereof that comprises the reflective photosensitive element within the first lens group of the five lens groups of the negative focal length-positive focal length-negative focal length-positive focal length-positive focal length configuration that is described herein. The zoom lens that is disclosed herein, however, achieves a magnification that is only on the order of 3×, making such a configuration incapable of fulfilling the demand for a magnification of 6× or greater.